MONDAY, Nov. 25, 2013 (HealthDay News) -- Kids near death because of severe flu infection have a better chance of survival if they are given antiviral medications early in their treatment, researchers say.

Children treated with antiviral drugs called neuraminidase inhibitors (NAIs) within the first 48 hours of serious flu symptoms developing are significantly more likely to survive, according to a study published online Nov. 25 in the journal Pediatrics.

"The benefit was more apparent for the most severely ill children, who required a ventilator to help with breathing," said co-author Dr. Janice Louie, chief of the influenza and respiratory diseases section at the California Department of Public Health's Center for Infectious Diseases.

In children rendered critically ill by the flu, treatment with NAIs reduced their risk of dying by 64 percent, the study found.

Researchers found that in recent years, however, fewer than two-thirds of severely ill children received NAIs while hospitalized for the flu.

Dr. Octavio Ramilo, a professor of pediatrics at Ohio State University, said a flu-stricken child who is sick enough to go to the hospital needs to receive antiviral therapies immediately.

"The minute you come to the hospital, we [should] start you on antiviral therapy," said Ramilo, who also is chief of infectious diseases at Nationwide Children's Hospital in Columbus, Ohio.

Doctors usually advise children with the flu to rest, drink lots of liquids and, if needed, use over-the-counter drugs to ease symptoms such as fever or congestion. But some people develop serious complications such as pneumonia that require hospitalization.

The study focused on nearly 800 patients younger than 18 who were treated in intensive-care units for the flu between April 2009 and September 2012.

Only 3.5 percent of kids who received NAI treatment during the first 48 hours ended up dying, the researchers found. By comparison, 9 percent of kids died who received NAIs between day eight and day 14 of their illness, and 26 percent died who received the medication after day 14.

Overall, 6 percent of kids treated with NAIs died from the flu, while 8 percent of kids died who didn't receive the medication.

Despite these numbers, hospitals appear reluctant to use NAIs when treating kids sick enough from the flu to require hospitalization.

About 90 percent of kids in the ICU with the flu received NAIs during the 2009 H1N1 flu pandemic, the researchers found. Only 63 percent of kids, however, received NAIs in the years following the pandemic.

"I'm not at all sure why that percentage was so low," said Dr. Rich Whitley, professor of pediatric infectious diseases at the University of Alabama at Birmingham. "There's no good reason for that."

Cost shouldn't be a factor, Louie said. "The cost of oseltamivir, the most commonly prescribed NAI, is approximately $7 per pill," she said. "The usual treatment course is one pill twice a day for five days, for a total $70."

The drug's side effects also should not be an issue. The main side effects are nausea and vomiting, which are much more common in children but occur in less than 10 percent of patients.

The explanation might be that smaller hospitals that treat fewer cases of the flu do not have the same level of experience and sense of urgency as hospitals that regularly deal with flu outbreaks, Ramilo said.

"If you work in a big teaching hospital, then you see these cases more often," he said. "The [doctors] think about it right away."

Some doctors also may not suspect flu when they start treating a very sick child. "Many clinicians may not initially consider influenza as a possible cause of respiratory illness or pneumonia, especially when it occurs outside of the peak of the influenza season," Louie said.

Another problem could be that intravenous forms of the antiviral medications currently are not available, Ramilo said. Kids have to take them by mouth, and very sick kids often are administered the medication via a tube snaked through their nose and down their throat.

Although this study lends hope for treating critically ill children, Ramilo and Whitley said flu shots remain the first and best line of defense against the flu.

"Children need to be immunized just like adults need to be immunized," Whitley said. "It's still the best approach we have to prevent influenza."